Oil well pump



R. c. wlLLnAMsf Nov. 28, 1939.

OIL WELL PUMP Filed May 14. 1956 m a U. y O E y W 2 M040 MHMJ d. 7 6 VANAF f f o wm@ d /f w K @m--m--E-hm i A im@ i f Patented Nov. 28, 1939 UNITED STATES ATENT OFFICE Application May 14,

1 Claim.

This invention relates to pumps for oil wells or the like, and is particularly ydirected. to the plunger and barrel elements of such a pump.

It has heretofore been the practice to provide a seal against leakage of oil between the plunger and barrel of an oil well pump either by a series of resilient cups of leather, rubber. or similar material, or by grinding the plunger to t closely in the barrel, leaving a clearance of some .002 of an inch and rely on the oil film to seal the pumps against leakage. In pumps of the latter type wear occurs between the plunger and barrel largely due to sand and other foreign substances working their way between the closely fitting surfaces and causing abrasion. 'I'he wear eventually progresses to such an extent that the oil lm will no longer hold a seal between the stationary barrel and the reciprocating plunger. At this time the pump must be pulled out of the Well and reground and tted, a machining operation which can usually be performed on special equipment not available in the oil field. This. means that either the well is shut down for an extended period or that a spare pumpmust be stocked to replace the worn one.

The primary object of the present invention is the provision of an oil sealed pump in which wor-n parts may be replaced, and the pump restored to its original close tting state in the field.

Another object of the invention is the provision of readily replaceable sealing elements, the manipulation of which does not require elaborate special tools when the pump is repaired.

Other objects and advantages will be apparent from the following detailed description and from the accompanying drawing, illustrative of the ine Vention, and in which- Figure l is a fragmentary sectional view, with some parts in full, of a pump embodying the present invention; Fig. 2 is a perspective View, with a part broken away, of one of the sealing elements; Fig. 3 is a fragmentary sectional view of a modied form of working barrel, and Fig. 4 is a diagrammatic sectional view of a plunger constructed in accordance with the present invention.

'I'he operation of a conventional deep well plunger pump actuated through a line of sucker rods is well known and will not be entered into. It will be appreciated that in most pumps of this character the stroke of the plunger is less than the length of the barrel in which it operates.

Referring to the drawing, the working barrel is designated generally by I, and the plunger by 1936, Serial No. 79,666

the numeral 2. The plunger is adapted to be reciprocated in the usual manner by a line of sucker rods 3, and is equipped with an upper ball check valve 4 and a lower ball check valve 6.

The plunger includes a hollow central stem or mandrel 8 which, as shown in Fig. 4 is tapered, being narrower at its upper end than at its lower end. 'Ihe extent of taper of the mandrel or stem may vary but is preferably about .002 of an inch in diameter for every six inches of length, the mandrel in the form shown being approximately 'four feet long. It will be appreciated that the taper shown in the drawing is greatly exaggerated for purposes of illustration.

Fitted closely about the tapered surface of thel plunger stem or mandrel 8 are a plurality of resilient sleeves i0, such as shown in Fig. 2. The sleeves are preferably formed from flat spring metal or other suitable resilient material so that they are capable of expansion. The spring material is coiled in a tight helix so that the convolutions lie closely together and contribute to prevent axial movement between adjacent turns. The inner surface of each sleeve lies closely adjacent the tapered surface of the mandrel, while the outer surface must necessarily be cylindrical so that there is no variation in the outer diameter of the entire plunger from top to bottom. Thus, in effect, the inner surface of each sleeve is tapered conversely to the taper of the plunger' and the thickness of each of the series is greater at the top than at the bottom. If the taper of the stem or mandrel 8 is .002 of an inch in diameter for each six inches in length, then the variation in thickness of each sleeve will be .002 of an inch from top to bottom since the sleeves are, in the form shown, approximately six inches long. It will be seen that when assembled on the plunger stem or mandrel, the series of sleeves form a continuously cylindrical surface on their exterior so that the plunger in use is similar to a cylindrical piston of metal. The series of sleeves ID are held on the mandrel or stem 8 by nuts I4 at the top and bottom, the nuts being received on threaded portions l of the mandred or stem.

When the pump has been in operation for some time, the diameter of the plunger will be reduced by reason of wear to such a point that an oil seal will no longer hold between the plunger and the adjacent working surface of the barrel. At this time, the plunger may be removed from the well, the lowermost of the sleeves I0 removed, the remainder o-f the sleeves forced down on the mandrel and the top one renewed. It will be seen that as each or" the series is forced dOWIl 0.11 the mandrel, the tapered inner surface overlies a new surface substantially .062 of an inch greater in diameter and the coiled metallic sleeve is expanded so that the ouside diameter is increased to the original dimension, if the wear has progressed so that the outside diameter Was reduced approximately .002 of an inch.

To manipulate the coiled resilient sleeve elements IU, it is necessary only to provide a simple means to expand the same by uncoilingr them slightly. For this reason, small holes l2 are drilled adjacent the top and bottom of each sleeve and are adapted to rec-eive a pin on whichy a turning force may be exerted to uncoil the sleeve.

The sleeves, wh-en uncoiled slightly, slip veryv readily over the tapered surface of the mandrel or stem 8 to assume their new position, replacing the next lower sleeve of the series. Thus, as the wear of the plunger progresses, the top sleeve ci the series will progressively replace each' of the sleeves below it until it iinally assumes the initial position of the lowerznost sleeve, after which it is thrown away.

In the conventional pump, the stroke oi the plunger is considerably shorter than the length of the barrel in which it operates, so that all of the wear in the barrel is concentrated L1 a comparatively short length adjacent the center. In order to adapt the barrel for repeated use of the plunger, the present invention provides a working portion of a smaller diameter adjacent the center of the barrel. shown at I may be formed by plating the interior of the barrel to decrease the wall diameter over a predetermined portion, and thus form shoulders Il at the top and bottom of the working portion. The width ofthe shoulders il may be approximately .066 of an inch, so that they are greatly exaggerated in the drawing. It will thus be seen that when wear occurs in the barrel and the plunger is renewed by moving the series of sleeves ii] downwardly to restore its original diameter, the plunger will still be able to t in the wc-rking portion of the barrel and form a seal ,v therewith. Obviously, the censtricted vworking portion of the barrel may known manner.

The present invention also contemplates the use of a plain, cylindrical plunger cooperating be formed in any well with a working barrel lined with a series of the coiled r-esilient sleeve elements. As shown in Fig. 3, the working barrel is made sectional so that the center, eiective portion 2i! may be provided with This portion diagrammatically a liner composed of the coiled resilient sleeve elebe moved down in the barrel as the wear progrosses.

It will be appreciated that by forming the sleeves l) of coiled material, the space between each convolution will, in effect, form an oil channel so that the working surfaces are properly lubricated at all times.

While the invention has been described in connection with a tapered mandrel and tapered barrel of particular length and dimensions, it should be expressly understood that various modications and changes may be made in the form and disposition of the parts and that any lrnownv means may be used to provide the necessary gradations of diameter over which the coiled sleeve elements lie when in use. It should be understood that such modifications and changes are contemplated and may be readily made without departing from the invention as described in the appended claim. l f

Having thus described my invention, what'I claim as new, and desire to secure by United.

States Letters Patent, is :y

An cilwell pump plunger working in cooperation' with a pump barrel to provide an oil seal thereu between, including a core member, a coiled resilient sleeve means on the core member inherently of less internal diameter than the external diameter of the core member and having a working diameter less than the internaldiameter of the pump barrel so as to provide space fo1 the' reception of a nlm of oil, and mea-ns carried by the core member and engaging the ends of the. sleeve means so to enable removal and replacement of the sleeve means kand by manipulation to provide oil channels between adjacent helices of the sleeve means to receive therein varying portions of the oil.. aforesaid `lor distribution in the space between the periphery ci the sleeve means and the internal walls of the pump barrel.

ROY C. WILLAMS. 

